DE112011103404T5 - Novel 3,9-linked oligocarbazole-based hosts containing DBT and DBF fragments separated by spacers. - Google Patents

Abstract

Compounds comprising a 3,9-linked oligocarbazole moiety and a dibenzothiophene, dibenzofuran, dibenzoselenophene, aza-dibenzothiophene, aza-dibenzofuran or aza-dibenzoselenophen are provided. The 3,9-linked oligocarbazole and the dibenzo or aza-dibenzo moieties are separated by an aromatic spacer. The compounds may be used as non-emitting phosphorescent OLED materials to provide devices having improved performance.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of US Application No. 12 / 900,925, filed on Oct. 8, 2010, the disclosure of which is expressly incorporated herein by reference in its entirety.

The claimed invention is made on behalf of and / or in conjunction with one or more of the following partners in a collaborative university research collaboration agreement: the Directors of the University of Michigan, Princeton University, the University of Southern California, and Universal Display Corporation , The contract was effective on and before the date on which the claimed invention came into existence and the claimed invention was the result of activities undertaken under the contract.

FIELD OF THE INVENTION

The present invention relates to organic light emitting devices (OLED). More particularly, the present invention relates to phosphorescent materials containing a 3,9-linked oligocarbazole and dibenzothiophene or dibenzofuran. These materials can provide devices with improved performance.

BACKGROUND

Optoelectronic devices utilizing organic materials are becoming more desirable for a variety of reasons. Many of the materials used to make such devices are relatively inexpensive, so that organic optoelectronic devices have the potential for cost advantages over inorganic devices. In addition, the inherent properties of organic materials, such as their flexibility, may make them well suited for particular applications, such as fabrication on a flexible substrate. Examples of organic optoelectronic devices include organic light emitting devices (OLEDs), organic phototransistors, organic photovoltaic cells, and organic photodetectors. For OLEDs, the organic materials may have performance advantages over conventional materials. For example, the wavelength at which an organic emissive layer emits light can generally be rapidly adjusted with suitable dopants.

OLEDs use thin organic films that emit light when voltage is applied to the device. OLEDs are becoming increasingly important for use in applications such as flat panel displays, lighting, and underground lighting. Several OLED materials and configurations will be available in the U.S. Pat. No. 5,844,363 . 6,303,238 and 5,707,745 which are incorporated herein by reference in their entirety.

One application for phosphorescent emitting molecules is a four-color display. Industry standards for such a display require pixels adapted to emit special colors called "saturated" colors. In particular, these standards require saturated red, green and blue pixels. The color can be measured using the CIE coordinates, which are well known in the art.

An example of a green emitting molecule is tris (2-phenylpyridine) iridium, which is indicated as Ir (ppy) 3, which has the structure:

Herein and in the following figures we represent the dative bond of nitrogen to metal (here Ir) as a straight line.

As used herein, the term "organic" includes polymeric materials as well as small molecules of organic materials that can be used to make organic optoelectronic devices. "Small molecules" refers to any organic material that is not a polymer, and "small molecules" can actually be relatively large. Small molecules may under certain circumstances contain repeating units. For example, when using a long-chain alkyl group as a substituent, a molecule is not removed from the class of "small molecules". For example, small molecules can also be incorporated into polymers as side groups on a polymer backbone or as part of the backbone. Small molecules can also serve as the core unit of a dendrimer, which consists of a series of chemical layers that build up on the core unit. The core unit of a dendrimer may be a fluorescent or phosphorescent small molecular emitter. A dendrimer may be a "small molecule" and it is believed that all dendrimers currently used in the field of OLEDs are small molecules.

As used herein, "top" means farthest from the substrate, while "bottom" means closest to the substrate. When a first layer is described as being disposed "above" a second layer, the first layer is located farther from the substrate. There may be another layer between the first and second layers unless it is stated that the first layer is in "contact" with the second layer. For example, a cathode may be described as being "over" an anode, even though there are various organic layers therebetween.

As used herein, "solution-based processable", capable of being dissolved, dispersed, or transported in and / or separated from a liquid medium, either in the form of a solution or a suspension, means.

A ligand may be termed "photoactive" if it is believed that the ligand contributes directly to the photoactive properties of an emissive material. A ligand may be termed an "auxiliary ligand" if it is believed that the ligand does not contribute to the photoactive properties of an emissive material, although an ancillary ligand may alter the properties of a photoactive ligand.

As used herein, and as one of ordinary skill in the art would generally appreciate, a first energy level of "highest occupied molecular orbital" (HOMO) or "lowest unoccupied molecular orbital" (LUMO) is "greater than" or "higher than". a second energy level of HOMO or LUMO when the first energy level is closer to the vacuum energy level. Since the ionization potentials (IP) are measured as negative energy relative to a vacuum level, a higher energy level of HOMO corresponds to an IP having a small absolute value (an IP that is less negative). Similarly, a higher energy level of LUMO corresponds to an electron affinity (EA) that has a smaller absolute value (an EA that is less negative). On a conventional energy level diagram, with the vacuum level at the top, the energy level of LUMO of a material is higher than the energy level of HOMO of the same material. A "higher" HOMO or LUMO energy level seems to be closer to the top of such a graph than a "lower" HOMO or LUMO energy level.

As used herein, and as generally understood by one of ordinary skill in the art, a first work function is "greater than" or "higher than" a second work function when the first work function has a higher absolute value. Since the work function is generally measured as negative numbers relative to the vacuum level, this means that a "higher" work function is more negative. On a conventional energy level diagram, with the vacuum level at the top, a "higher" work function is illustrated than in the downward direction farther away from the vacuum level. Thus, the definitions of HOMO and LUMO energy levels follow a different convention than the work function functions.

More detailed information about OLEDs and the definitions described above can be found in the U.S. Patent No. 7,279,704 which is incorporated herein by reference in its entirety.

BRIEF SUMMARY OF THE INVENTION

Compounds comprising a 3,9-linked oligocarbazole and a dibenzo or azadibenzo moiety are provided. The compounds have the following formula:

n is 1 to 20. Preferably n is 1, 2 or 3. Most preferably, n is 1. Each of R ' ₁ , R' ₂ , R ' ₃ and R' ₄ independently represents mono-, di-, tri-, or tetrasubstitutions. R ' ₁ , R' ₂ , R ' ₃ and R' ₄ are independently selected from the group consisting of hydrogen, deuterium, alkyl, alkoxy, amino, alkenyl, alkynyl, arylalkyl, aryl and heteroaryl. R _a and R _b independently represent mono-, di-, tri- or tetrasubstitutions. R _a and R _b are independently selected from the group consisting of hydrogen, deuterium, alkyl, alkoxy, amino, alkenyl, alkynyl, arylalkyl, aryl and heteroaryl selected. X is an aryl or heteroaryl linker which is further substituted with R _a . Y is dibenzothiophene, dibenzofuran, dibenzoselenophene, aza-dibenzothiophene, aza-dibenzofuran or aza-dibenzoselenophen, which is further substituted by R _b . Preferably Y is 2-dibenzothiophenyl, 4-dibenzothiophenyl, 2-dibenzofuranyl or 4-dibenzofuranyl.

A, B, C und D sind unabhängig voneinander aus der Gruppe ausgewählt, die besteht aus:

In one aspect, X is

A, B, C and D are independently selected from the group consisting of:

A, B, C and D are optionally further substituted with R _a . Each of p, q, r and s is 0, 1, 2, 3 or 4. p + q + r + s is at least 1.

Specific examples of the compounds are provided. In one aspect, the compound is selected from the group consisting of compound 1 through compound 83.

An organic light-emitting device is also provided. The device comprises an anode, a cathode and a first organic layer disposed between the anode and the cathode. The organic layer comprises a compound having the following formula:

n is 1 to 20. Preferably n is 1, 2 or 3. Most preferably, n is 1. Each of R ' ₁ , R' ₂ , R ' ₃ and R' ₄ independently represents mono-, di-, tri-, or tetrasubstitutions. R ' ₁ , R' ₂ , R ' ₃ and R' ₄ are independently selected from the group consisting of hydrogen, deuterium, alkyl, alkoxy, amino, alkenyl, alkynyl, arylalkyl, aryl and heteroaryl. R _a and R _b independently represent mono-, di-, tri- or tetrasubstitutions. R _a and R _b are independently selected from the group consisting of hydrogen, deuterium, alkyl, alkoxy, amino, alkenyl, alkynyl, arylalkyl, aryl and heteroaryl selected. X is an aryl or heteroaryl linker which is further substituted with R _a . Y is dibenzothiophene, dibenzofuran, dibenzoselenophene, aza-dibenzothiophene, aza-dibenzofuran or aza-dibenzoselenophen, which is further substituted by R _b . Preferably Y is 2-dibenzothiophenyl, 4-dibenzothiophenyl, 2-dibenzofuranyl or 4-dibenzofuranyl.

A, B, C und D sind unabhängig voneinander aus der Gruppe ausgewählt, die besteht aus:

In one aspect, X is

A, B, C and D are independently selected from the group consisting of:

A, B, C and D are optionally further substituted with R _a . Each of p, q, r and s is 0, 1, 2, 3 or 4. p + q + r + s is at least 1.

Specific examples of devices comprising the compounds are provided. In one aspect, the compound is selected from the group consisting of compound 1 through compound 83.

In one aspect, the first organic layer is an emitting layer and the

In another aspect, the first organic layer further comprises an emitting dopant having the formula

A is a 5- or 6-membered carbocyclic or heterocyclic ring. R ₁ , R ₂ and R ₃ independently represent mono-, di-, tri- or tetrasubstituents. Each of R ₁ , R ₂ and R ₃ is independently of the group t, selected from hydrogen, deuterium, alkyl, alkoxy , Amino, alkenyl, alkynyl, arylalkyl, aryl and heteroaryl. n is 1, 2 or 3. X-Y is an auxiliary ligand.

In another aspect, the emitting dopant is selected from the group consisting of:

In yet another aspect, the device further comprises a second organic layer that is a non-emitting layer, and the compound of the formula I is a material in the second organic layer.

In one aspect, the second organic layer is an electron transport layer and the compound of formula I is an electron transport material in the second organic layer.

In another aspect, the second organic layer is a blocking layer and the compound of formula I is a blocking material in the second organic layer.

In one aspect, the first organic layer is applied using solution-based processing.

In one aspect, the device is an organic light emitting device. In another aspect, the device is a consumer good.

BRIEF DESCRIPTION OF THE DRAWINGS

1 shows an organic light-emitting device.

2 shows an inverted organic light emitting device that does not have a separate electron transport layer.

3 shows a compound containing a 3,9-linked oligocarbazole and one dibenzo or aza-dibenzo group.

DETAILED DESCRIPTION

In general, an OLED includes at least one organic layer interposed therebetween and electrically connected to an anode and a cathode. When a current is applied, the anode injects holes and the cathode injects electrons into the organic layer (s). The injected holes and electrons each travel to the oppositely charged electrode. When an electron and a hole are located on the same molecule, an "exciton" is formed, which is a localized electron-hole pair that has an excited energy state. Light is emitted when the exciton relaxes via a photoemission mechanism. In some cases, the exciton may be located on an excimer or an exciplex. Radiation-free mechanisms, such as thermal relaxation, may also occur, but are generally considered undesirable.

The first OLEDs used emitting molecules that emit light from their singlet states ("fluorescence"), such as in U.S. Pat U.S. Patent No. 4,769,292 which is incorporated herein by reference in its entirety. Fluorescence emission generally occurs in a time frame of less than 10 nanoseconds.

More recently, OLEDs have been detected that have emitting materials that emit light from triplet states ("phosphorescence"). Baldo et al., "Highly Efficient Phosphorescent Emission from Organic Electroluminescent Devices," Nature, vol. 395, 151-154, 1998; ( "Baldo-I") and Baldo et al., "Very high-efficiency green organic light-emitting devices based on electrophosphorescence," Appl. Phys. Lett., Vol. 75, no. 3, 4-6 (1999) ("Baldo-II") , which are incorporated herein by reference in their entirety. Phosphorescence becomes more detailed in the U.S. Patent No. 7,279,704 in columns 5-6, which are incorporated herein by reference.

1 shows an organic light-emitting device 100 , The figures are not necessarily drawn to scale. contraption 100 can be a substrate 110 , an anode 115 a hole injection layer 120 a hole transport layer 125 , an electron blocking layer 130 , an emitting layer 135 a hole blocking layer 140 , an electron transport layer 145 , an electron injection layer 150 , a protective layer 155 and a cathode 160 include. cathode 160 is a composite cathode with a first conductive layer 162 and a second conductive layer 164 , contraption 100 can be prepared by depositing the described layers in order. The properties and functions of these various layers, as well as example materials, are described in greater detail in the U.S. Patent No. 7,279,704 in columns 6-10, which are incorporated herein by reference.

Further examples of each of these layers are available. For example, a flexible and transparent substrate-anode combination in the U.S. Patent No. 5,844,363 which is incorporated herein by reference in its entirety. An example of a p-doped hole transport layer is m-MTDATA doped with F4-TCNQ in a molar ratio of 50: 1, as disclosed in U.S. Patent Application No. 2003/0230980, which is incorporated herein by reference in its entirety. Examples of emissive materials and host materials are described in U.S. Pat U.S. Patent No. 6,303,238 Thompson et al. which is incorporated herein by reference in its entirety. An example of an n-doped electron transport layer is BPhen doped with Li in a molar ratio of 1: 1, as disclosed in U.S. Patent Application No. 2003/0230980, which is incorporated herein by reference in its entirety. The U.S. Patent No. 5,703,436 and 5,707,745 , which are incorporated herein by reference in their entirety, disclose examples of cathodes containing composite cathodes having a thin film of metal, such as Mg: Ag, with an overlying transparent, electrically conductive, sputter deposited ITO layer. The theory and use of blocking layers will be discussed in more detail in the U.S. Patent No. 6,097,147 and US Patent Application No. 2003/0230980, which are incorporated herein by reference in their entirety. Examples of injection layers are provided in U.S. Patent Application No. 2004/0174116, which is incorporated herein by reference in its entirety. A description of protective layers can be found in U.S. Patent Application No. 2004/0174116, which is incorporated herein by reference in its entirety.

2 shows an inverted OLED 200 , The device includes a substrate 210 , a cathode 215 , an emitting layer 220 a hole transport layer 225 and an anode 230 , contraption 200 can be prepared by depositing the described layers in the correct order. Because the most common OLED configuration has a cathode overlying the anode and device 200 a cathode 215 that under anode 230 is arranged can 200 be referred to as an "inverted" OLED. Materials similar to those related to device 100 can be described in the corresponding layers of device 200 be used. 2 provides an example of how some layers from the structure of device 100 can be omitted.

The simply layered structure that is in 1 and 2 is provided by way of non-limiting example and it is to be understood that embodiments of the invention may be used in conjunction with numerous other structures. The specific materials and structures described are exemplary and other materials and structures may be used. Functional OLEDs can be obtained by combining different layers described in various ways, or layers based on design, performance, and cost factors can be omitted altogether. Other non-specifically described layers can also be included. Other materials than those specifically described may be used. Although many of the examples provided herein describe different layers comprising only a single material, it will be understood that combinations of materials, such as a mixture of host and dopant, or more generally a mixture, may be used. The layers can also have different partial layers. The names used to refer to the various layers herein are not to be considered as strictly limiting. For example, transported in device 200 the hole transport layer 225 Holes and inject holes into the emitting layer 220 and may be described as a hole transport layer or a hole injection layer. In an embodiment, an OLED may be described as having an "organic layer" disposed between a cathode and an anode. This organic layer may comprise a single layer, or it may further comprise multiple layers of various organic materials, such as for example 1 and 2 described.

It is also possible to use structures and materials which are not specifically described here, such as OLEDs, which consist of polymer materials (PLEDs), as described for example in US Pat U.S. Patent No. 5,247,190 by Friend et al. which is incorporated herein by reference in its entirety. As another example, OLEDs having a single organic layer may be used. OLEDs can be stacked, as it is for example in the U.S. Patent No. 5,707,745 by Forrest et al. which is incorporated herein by reference in its entirety. The OLED structure may differ from the single layered structure found in 1 and 2 is illustrated. For example, the substrate may include an angular reflective surface to enhance the outcoupling, such as a mesa structure as shown in U.S. Pat U.S. Patent No. 6,091,195 by Forrest et al. is described, and / or a structure with recesses, as shown in the U.S. Patent No. 5,834,893 by Bulovic et al. which are incorporated herein by reference in their entirety.

Unless otherwise stated, each of the layers of the various embodiments may be deposited by any suitable method. For the organic layers, preferred methods include thermal evaporation, ink jet, such as in U.S. Pat U.S. Patent No. 6,013,982 and 6,087,196 as fully incorporated herein by reference, organic vapor deposition (OVPD) as disclosed in US Pat. No. 6,337,102 to Forrest et al. which is incorporated herein by reference in its entirety, and Organic Vapor Jet Printing (OVJP) deposition as described in U.S. Patent Application Serial No. US Pat. 10 / 233,470, which is incorporated herein by reference in its entirety. Other suitable deposition methods include spin coating and other solution based processes. Solution-based processes are preferably carried out in nitrogen or an inert atmosphere. For the other layers, preferred methods include thermal evaporation. Preferred patterning methods include deposition through a mask, cold welding, as in FIGS U.S. Patent No. 6,294,398 and 6,468,819 which are incorporated herein by reference in their entirety and structuring associated with some of the deposition methods, such as ink jet and OVJD. Other methods may be used. The materials to be deposited can be modified to be compatible with a specific deposition process. For example, substituents such as alkyl and aryl groups, which are branched or unbranched and preferably contain at least 3 carbons, can be used in small molecules to make them more suitable for solution processing. Substituents of 20 carbons or more may be used and 3 to 20 carbons are a preferred range. Materials having asymmetric structures may have better processability in solution than those having symmetric structures since asymmetric materials may have a lower tendency to recrystallize. Dendrimer substituents can be used to make small molecules more suitable for solution processing.

Devices made in accordance with embodiments of the invention may be integrated into a variety of consumer products, including flat panel displays, computer monitors, televisions, billboards, indoor and outdoor lighting and / or signaling lamps, head-up displays, fully transparent screens, flexible displays , Laser printers, phones, cell phones, PDA (PDA) computers, laptop computers, digital cameras, camcorders, viewfinders, microdisplays, vehicles, a large wall panel, a theater or stage screen, or a sign. Various control mechanisms may be used to control devices made in accordance with the present invention, including passive matrix and active matrix. Many of the devices are intended for use in a temperature range that is comfortable to humans, such as 18 degrees C to 30 degrees C, and more preferably at room temperature (20 to 25 degrees C).

The materials and structures described herein may find applications in devices that are not OLEDs. For example, other opto-electronic devices such as organic solar cells and organic photodetectors may utilize the materials and structures. More generally, organic devices, such as organic transistors, may utilize the materials and structures.

The terms halo, halo, alkyl, cycloalkyl, alkenyl, alkynyl, arylalkyl, heterocyclic group, aryl, aromatic group and heteroaryl are known in the art and are described in the U.S. Patent 7,279,704 in columns 31-32, which are incorporated herein by reference.

Novel compounds are provided which contain a 3,9-linked oligocarbazole and a dibenzo or azadibenzo group (illustrated in U.S. Pat 3 ). In particular, the compounds comprise a 3,9-linked oligocarbazole moiety and a dibenzothiophene (DBT), dibenzofuran (DBF), dibenzoselenophene, aza-dibenzothiophene (aza-DBT), aza-dibenzofuran (aza-DBF), or aza-dibenzo-furan. dibenzoselenophen, such that the 3,9-linked oligocarbazole moiety and the dibenzo or aza-dibenzo moiety are separated by an aromatic spacer. The compounds can be used as non-emitting materials for phosphorescent OLEDs. For example, the compounds may be used as host materials, electron transport materials, and / or materials in a blocking layer.

As mentioned above, the compounds consist of 3,9-linked oligocarbazole and dibenzo moiety, e.g. DBT or DBF fragments, or aza-dbenzo moiety, e.g. Aza-DBT or aza-DBF separated by aromatic spacers. Without being limited by any theory as to how embodiments of the invention work, the HOMO of the compound is determined from the 3,9-linked oligocarbazole moiety and the LUMO is determined by the dibenzo moiety or azadibenzo moiety. The aromatic spacer may be designed to expand the conjugation. Without being bound by theory, it is believed that compounds with extended conjugation have improved stability because the charge is delocalized over a greater range. The connection provides a good tunability of the HOMO and the LUMO. The compounds showed improved device performance (i.e., efficiency, voltage, and lifetime) when used as a host for a light blue PHOLED. It is believed that selecting the 3,9-linked oligocarbazole and dibenzo or aza-dbenzo moieties and their association with each other via the aromatic spacer can preserve the triplet value of these compounds in the blue portion of the spectrum. Not only can these compounds serve as a host, but they can also function as an electron transport material or material in a blocking layer.

In addition to improved charge balance and charge stability, the compounds provided herein can also provide better film formation. In particular, materials having an asymmetric structure can provide improved film formation. The improved film formation may be a result of the increased tendency to remain amorphous due to the asymmetric structure of the compound even at higher temperatures, as evidenced by unexpected results from solution-based processing using the compounds as a host material.

Compounds comprising a 3,9-linked oligocarbazole and a dibenzo or aza-dibenzo moiety are provided. The compound has the following formula:

n is 1 to 20. Preferably n is 1, 2 or 3. Most preferably, n is 1. Each of R ' ₁ , R' ₂ , R ' ₃ and R' ₄ independently represents mono-, di-, tri-, or tetrasubstitutions. R ' ₁ , R' ₂ , R ' ₃ and R' ₄ are independently selected from the group consisting of hydrogen, deuterium, alkyl, alkoxy, amino, alkenyl, alkynyl, arylalkyl, aryl and heteroaryl. R _a and R _b independently represent mono-, di-, tri- or tetrasubstitutions. R _a and R _b are independently selected from the group consisting of hydrogen, deuterium, alkyl, alkoxy, amino, alkenyl, alkynyl, arylalkyl, aryl and heteroaryl selected. X is an aryl or heteroaryl linker which is further substituted with R _a . Y is dibenzothiophene, dibenzofuran, dibenzoselenophene, aza-dibenzothiophene, aza-dibenzofuran or aza-dibenzoselenophen, which is further substituted by R _b . Preferably Y is 2-dibenzothiophenyl, 4-dibenzothiophenyl, 2-dibenzofuranyl or 4-dibenzofuranyl.

A, B, C und D sind unabhängig voneinander aus der Gruppe ausgewählt, die besteht aus:

In one aspect, X is

A, B, C and D are independently selected from the group consisting of:

A, B, C and D are optionally further substituted with R _a . Each of p, q, r and s is 0, 1, 2, 3 or 4. p + q + r + s is at least 1.

Specific examples of the compounds are provided. In one aspect, the compound is selected from the group consisting of:

Also, a first device comprising an organic light-emitting device is provided. The organic light emitting device comprises an anode, a cathode, and a first organic layer disposed between the anode and the cathode. The organic layer comprises a compound having the following formula:

n is 1 to 20. Preferably n is 1, 2 or 3. Most preferably, n is 1. Each of R ' ₁ , R' ₂ , R ' ₃ and R' ₄ independently represents mono-, di-, tri-, or tetrasubstitutions. R ' ₁ , R' ₂ , R ' ₃ and R' ₄ are independently selected from the group consisting of hydrogen, deuterium, alkyl, alkoxy, amino, alkenyl, alkynyl, arylalkyl, aryl and heteroaryl. R _a and R _b independently represent mono-, di-, tri- or tetrasubstitutions. R _a and R _b are independently selected from the group consisting of hydrogen, deuterium, alkyl, alkoxy, amino, alkenyl, alkynyl, arylalkyl, Aryl and heteroaryl selected. X is an aryl or heteroaryl linker which is further substituted with R _a . Y is dibenzothiophene, dibenzofuran, dibenzoselenophene, aza-dibenzothiophene, aza-dibenzofuran or aza-dibenzoselenophen, which is further substituted by R _b . Preferably Y is 2-dibenzothiophenyl, 4-dibenzothiophenyl, 2-dibenzofuranyl or 4-dibenzofuranyl.

A, B, C und D sind unabhängig voneinander aus der Gruppe ausgewählt, die besteht aus:

In one aspect, X is

A, B, C and D are independently selected from the group consisting of:

A, B, C and D are optionally further substituted with R _a . Each of p, q, r and s is 0, 1, 2, 3 or 4. p + q + r + s is at least 1.

Specific examples of devices comprising the compounds are provided. In one aspect, the compound is selected from the group consisting of compound 1 through compound 83.

In one aspect, the first organic layer is an emitting layer and the

In another aspect, the first organic layer further comprises an emitting dopant having the formula

A is a 5- or 6-membered carbocyclic or heterocyclic ring. R _1, R ₂ and R ₃ independently of one another mono-, di-, tri- or Tetrasubstituenten. Each of R _1, R ₂ and R ₃ is independently selected from the group consisting of hydrogen, deuterium, alkyl, alkoxy, amino , Alkenyl, alkynyl, arylalkyl, aryl and heteroaryl. n is 1, 2 or 3. XY is an auxiliary ligand.

In another aspect, the emitting dopant is selected from the group consisting of:

In yet another aspect, the first device further comprises a second organic layer that is a non-emitting layer, and the compound of the formula I is a material in the second organic layer.

In one aspect, the second organic layer is an electron transport layer and the compound of formula I is an electron transport material in the second organic layer.

In another aspect, the second organic layer is a blocking layer and the compound of formula I is a blocking material in the second organic layer.

In one aspect, the first organic layer is applied using solution-based processing.

In one aspect, the first device is an organic light emitting device. In another aspect, the first device is a consumer product.

There are also several other embodiments; however, these additional embodiments are less preferred.

Compounds comprising a carbazole or a 3,9-linked oligocarbazole and a dibenzo or aza-dibenzo moiety are provided. The compounds have the following formula:

n is 0 to 20. Preferably n is 1 to 20. More preferably n is 1, 2 or 3. Most preferably, n is 1. Each of R ' ₁ , R' ₂ , R ' ₃ and R' ₄ is independently Mono, di, tri or tetrasubstituted. R ' ₁ , R' ₂ , R ' ₃ and R' ₄ are independently selected from the group consisting of hydrogen, deuterium, alkyl, alkoxy, amino, alkenyl, alkynyl, arylalkyl , Aryl and heteroaryl selected. R _a and R _b independently represent mono-, di-, tri- or tetrasubstitutions. R _a and R _b are independently selected from the group consisting of hydrogen, deuterium, alkyl, alkoxy, amino, alkenyl, alkynyl, arylalkyl, aryl and heteroaryl selected. X is an aryl or heteroaryl linker which is further substituted with R _a . Y is dibenzothiophene, dibenzofuran, dibenzoselenophene, aza-dibenzothiophene, aza-dibenzofuran or aza-dibenzoselenophen, which is further substituted by R _b . Preferably Y is 2-dibenzothiophenyl, 4-dibenzothiophenyl, 2-dibenzofuranyl or 4-dibenzofuranyl.

When n is 0, X is an aryl linker comprising at least two phenylene groups, and Y is 4-dibenzothiophene.

A, B, C und D sind unabhängig voneinander aus der Gruppe ausgewählt, die besteht aus:

In one aspect, X is

A, B, C and D are independently selected from the group consisting of:

A, B, C and D are optionally further substituted with R _a . Each of p, q, r and s is 0, 1, 2, 3 or 4. p + q + r + s is at least 1.

In one aspect, n is 0, X is an aryl linker comprising at least two phenylene groups, and Y is 4-dibenzothiophene. In another aspect, X is selected from the group consisting of:

X is further substituted with R _a . Without being bound by theory, it is believed that compounds comprising a carbazole and a 4-dibenzothiophene separated by at least two phenylene groups can be used in various organic layers in a device to provide improved device life. For example, a carbazole and a 4-dibenzothiophene separated by two phenylene rings may be a host material, while a carbazole and a 4-dibenzothiophene separated by three phenylene rings may be a blocking material.

Specific examples of the compounds are provided. In one aspect, the compound is selected from the group consisting of:

COMBINATION WITH OTHER MATERIALS

The materials described herein as useful for a particular layer in an organic light emitting device may be used in combination with a wide variety of other materials present in the device. For example, the emissive dopants disclosed herein may be used in conjunction with a wide range of hosts, transport layers, blocking layers, injection layers, electrodes, and other layers that may be present. The materials described or referred to below are nonlimiting examples of materials that may be useful in combination with the compounds disclosed herein, and one of ordinary skill in the art can simply look up the literature for other materials identify who may be useful in the combination.

HIL / HTL:

A hole injecting / transporting material to be used in embodiments of the present invention is not particularly limited, and any compound may be used as far as the compound is typically used as a hole injecting / transporting material. Examples of the material include, but are not limited to: a phthalocyanine or porphyrin derivative; an aromatic amine derivative; an indolocarbazole derivative; a polymer containing fluorohydrocarbon; a polymer having conductivity dopants; a conductive polymer such as PEDOT / PSS; a self-assembling monomer derived from compounds such as phosphonic acid and silane derivatives; a metal oxide derivative such as MoOx; an organic semiconductive p-compound such as 1,4,5,8,9,12-hexaazatriphenylenehexacarbonitrile; a metal complex, as well as crosslinkable compounds.

Examples of aromatic amine derivatives used in HIL or HTL include, but are not limited to, the following general structures:

Each of Ar ¹ to Ar ⁹ is selected from the group consisting of aromatic cyclic hydrocarbon compounds such as benzene, biphenyl, triphenyl, triphenylene, naphthalene, anthracene, phenalen, phenanthrene, fluorene, pyrene, chrysene, perylene, azulene; from the group consisting of aromatic heterocyclic compounds, such as dibenzothiophene, dibenzofuran, dibenzoselenophene, furan, Thiophene, benzofuran, benzothiophene, benzoselenophene, carbazole, indolocarbazole, pyridylindole, pyrrolodipyridine, pyrazole, imidazole, triazole, oxazole, thiazole, oxadiazole, oxatriazole, dioxazole, thiadiazole, pyridine, pyridazine, pyrimidine, pyrazine, triazine, oxazine, oxathiazine, oxadiazine, Indole, benzimidazole, indazole, indoxazine, benzoxazole, benzisoxazole, benzothiazole, quinoline, isoquinoline, cinnoline, quinazoline, quinoxaline, naphthyridine, phthalazine, pteridine, xanthene, acridine, phenazine, phenothiazine, phenoxazine, benzofuropyridine, furodipyridine, benzothienopyridine, thienodipyridine, benzoselenophenopyridine and Selenophenodipyridin; and from the group consisting of from 2 to 10 cyclic structural units which are groups of the same or different type selected from the group consisting of aromatic cyclic hydrocarbons and the group of aromatic heterocyclic hydrocarbons directly or via at least one of an oxygen atom, a Nitrogen atom, a sulfur atom, a silicon atom, a phosphorus atom, a boron atom are bonded to each other, a chain structural unit and the aliphatic cyclic group. Wherein each Ar is further substituted with a substituent selected from the group consisting of hydrogen, deuterium, alkyl, alkoxy, amino, alkenyl, alkynyl, arylalkyl, heteroalkyl, aryl and heteroaryl.

In one aspect Ar ¹ to Ar ^{9 is} independently selected from the group consisting of:

k is an integer from 1 to 20; X ¹ to X ⁸ is CH or N; Ar ¹ has the same group defined above.

Examples of metal complexes used in HIL or HTL include, but are not limited to, the following general formula:

M is a metal having an atomic weight greater than 40; (Y ¹ -Y ² ) is a bidentate ligand, Y ¹ and Y ² are independently selected from C, N, O, P and S; L is an auxiliary ligand; m is an integer value of 1 to the maximum number of ligands that can be attached to the metal; and m + n is the maximum number of ligands that can be attached to the metal.

In one aspect, (Y ¹ -Y ² ) is a 2-phenylpyridine derivative.

In another aspect, (Y ¹ -Y ² ) is a carbene ligand.

In another aspect, M is selected from Ir, Pt, Os and Zn.

In another aspect, the metal complex in solution has a minimum oxidation potential of less than about 0.6 V over the Fc ⁺ / Fc pair.

Host (Host):

The light-emitting layer of the organic EL device of embodiments of the present invention preferably contains at least one metal complex as a light-emitting material, and may contain a host material in which the metal complex is used as a doping material. Examples of the host material are not particularly limited, and any metal complexes or Organic compounds can be used if the triplet energy of the host is greater than that of the dopant.

Examples of metal complexes used as hosts preferably have the following general formula:

M is a metal; (Y ³ -Y ⁴ ) is a bidentate ligand, Y ³ and Y ⁴ are independently selected from C, N, O, P and S; L is an auxiliary ligand; m is an integer value of 1 to the maximum number of ligands that can be attached to the metal; and m + n is the maximum number of ligands that can be attached to the metal.

In one aspect, the metal complexes are:

(O-N) is a bidentate ligand that has metal coordinated to the atoms O and N.

In another aspect, M is selected from Ir and Pt.

In another aspect, (Y ³ -Y ⁴ ) is a carbene ligand.

Examples of organic groups used as hosts are selected from the group consisting of aromatic cyclic hydrocarbon compounds, such as benzene, biphenyl, triphenyl, triphenylene, naphthalene, anthracene, phenals, phenanthrene, fluorene, pyrene, chrysene, perylene, azulene; from the group consisting of aromatic heterocyclic compounds such as dibenzothiophene, dibenzofuran, dibenzoselenophene, furan, thiophene, benzofuran, benzothiophene, benzoselenophene, carbazole, indolocarbazole, pyridylindole, pyrrolodipyridine, pyrazole, imidazole, triazole, oxazole, thiazole, oxadiazole, oxatriazole, dioxazole , Thiadiazole, pyridine, pyridazine, pyrimidine, pyrazine, triazine, oxazine, oxathiazine, oxadiazine, indole, benzimidazole, indazole, indoxazine, benzoxazole, benzisoxazole, benzothiazole, quinoline, isoquinoline, cinnoline, quinazoline, quinoxaline, naphthyridine, phthalazine, pteridine, xanthene , Acridine, phenazine, phenothiazine, phenoxazine, benzofuropyridine, furodipyridine, benzothienopyridine, thienodipyridine, benzoselenophenopyridine and selenophenodipyridine; and from the group consisting of from 2 to 10 cyclic structural units which are groups of the same or different type selected from the group consisting of aromatic cyclic hydrocarbons and the group of aromatic heterocyclic hydrocarbons directly or via at least one of an oxygen atom, a Nitrogen atom, a sulfur atom, a silicon atom, a phosphorus atom, a boron atom are bonded to each other, a chain structural unit and the aliphatic cyclic group. Wherein each group is further substituted with a substituent selected from the group consisting of hydrogen, deuterium, alkyl, alkoxy, amino, alkenyl, alkynyl, arylalkyl, heteroalkyl, aryl and heteroaryl.

In one aspect, the host compound contains at least one of the following groups in the molecule:

R ¹ to R ⁷ are independently selected from the group consisting of hydrogen, deuterium, alkyl, alkoxy, amino, alkenyl, alkynyl, arylalkyl, heteroalkyl, aryl and heteroaryl; when it is aryl or heteroaryl, it has a similar definition to that of Ar mentioned above.

k is an integer from 0 to 20.

X ¹ to X ⁸ is selected from CH or N.

HBL:

A hole blocking layer (HBL) can be used to reduce the number of holes and / or excitons leaving the emissive layer. The presence of such a blocking layer in a device can yield substantially higher efficiencies compared to a similar device that lacks a blocking layer. Also, a blocking layer can be used to limit the emission to a desired region of an OLED.

In one aspect, a compound used in HBL contains the same molecule used as the host described above.

k ist eine ganze Zahl von 0 bis 20; L ist ein Hilfsligand, m ist eine ganze Zahl von 1 bis 3.In another aspect, the compound used in the HBL contains at least one of the following groups in the molecule:

k is an integer from 0 to 20; L is an auxiliary ligand, m is an integer from 1 to 3.

ETL:

The electron transport layer (ETL) may include a material capable of transporting electrons. The electron transport layer may be intrinsic (undoped) or doped. Doping can be used be used to increase the conductivity. Examples of the ETL material are not particularly limited, and any metal complexes or organic compounds may be used as long as they are typically used to transport electrons.

In one aspect, the compound used in the ETL contains at least one of the following groups in the molecule:

R ¹ is selected from the group consisting of hydrogen, deuterium, alkyl, alkoxy, amino, alkenyl, alkynyl, arylalkyl, heteroalkyl, aryl and heteroaryl; when it is aryl or heteroaryl, it has a similar definition to that of Ar mentioned above.

Ar ¹ to Ar ³ have a similar definition to that of Ar mentioned above.

k is an integer from 0 to 20.

X ¹ to X ⁸ is selected from CH or N.

In another aspect, the metal complexes used in the ETL include, but are not limited to, the following general formula:

(O-N) or (N-N) is a bidentate ligand having metal coordinated with the atoms O, N or N, N; L is an auxiliary ligand; m is an integer value of 1 to the maximum number of ligands that can be attached to the metal.

In the above-mentioned compounds used in each layer of the OLED device, the hydrogen atoms may be partially or completely deuterated.

In addition to and / or in combination with the materials disclosed herein, many hole injecting materials, hole transporting materials, host materials, doping materials, exciton / hole blocking materials, electron transporting and electron injecting materials can be used in an OLED. Non-limiting examples of the materials that can be used in an OLED in combination with materials disclosed herein are listed in Table 1 below. Table 1 lists non-limiting classes of materials, non-limiting examples of compounds of each class, and references in which the materials are disclosed. TABLE

EXPERIMENTAL PART

connection Examples

Synthesis of Compound 1

Step 1. The solution of carbazole and potassium iodide in 550 mL of acetic acid was heated to 120 ° C to dissolve the reactants and then allowed to cool back to 100 ° C. At this temperature potassium iodate was added slowly and the reaction mixture was stirred for 2 h at 100 ° C. The reaction mixture was then allowed to cool to 60 ° C and 500 ml of water was added, resulting in the formation of gray precipitate. The solid material was filtered off and washed with hot water. It was then dissolved in CH ₂ Cl ₂ ; This solution was washed carefully with NaHCO ₃ aq., NaHSO ₃ aq., brine, then dried over sodium sulfate. The volume was reduced to form a slurry mixture, then cooled and held at room temperature for at least 30 minutes, solid material was filtered off, washed once with a minimum of CH ₂ Cl ₂ and dried. It was placed in a 500 ml flask, 100 ml EtOAc was added, rotary evaporated at 60 ° C for 20 minutes at 60 ° C, then solvent was pumped off to form a slurry mixture, then 200 ml hexanes were added, and held at 55 ° C for 15 minutes without vacuum. Then cooled to room temperature, held for 30 minutes, briefly sonicated for 3 minutes, solid material filtered off and washed with plenty of hexane. The material was dried under vacuum to give 24 g (40% yield) of pure.

Step 2. 2-iodocarbazole (29.2 g, 0.1 mol) was dissolved in 200 ml of dry acetone, then potassium hydroxide (7.84 g, 0.14 mol) was added and stirred until complete dissolution; followed by slow addition of tosyl chloride (22.8 g, 0.12 mol). The reaction mixture was refluxed for 3 hours. The reaction mixture was cooled to 60 to 70 ° C and poured into water while stirring at a constant speed; Stirring was continued for a while after the entire amount had been poured. A product hit the glass wall; after 30 minutes, water was decanted off, the precipitate was washed with water, then twice with EtOH. The residue material was dissolved in CH ₂ Cl ₂ and partially evaporated to solidification, a large volume of EtOH was added and all of the CH ₂ Cl _{2 was} further evaporated (repeated several times). Stirred at 60 ° C for 10 minutes, then cooled, held at 20 ° C and filtered, the precipitate was washed with EtOH and dried, yielding 40 g (90% yield) of pure 3-iodo-9-tosyl-9H-carbazole ,

Step 3. 3-iodo-9-tosyl-9H-carbazole (31.29 g, 0.07 mol), Cu (I) iodide (1.33 g, 0.007 mol), potassium phosphate (29.7 g, 0 , 14 mol) and carbazole (14.03 g, 0.084 mol) were combined in a 3-necked flask, degassed 4 times, and cyclohexane-1,3-diamine (1.14 g, 0.01 mol) in 400 ml of anhydrous toluene was added. Degassed again, reaction flask filled with N ₂ and heated at reflux overnight (20 h). The reaction mixture was cooled to 20 ° C, filtered through a plug of silica gel filled with celite, washed with toluene; the plug was washed with CH ₂ Cl ₂ , combined organic fractions were evaporated. The residue was dissolved in 100 ml CH ₂ Cl ₂ and 300 ml EtOH added; then CH ₂ Cl _{2 was} evaporated. The residue in EtOH was held at 70 ° C for 20 minutes, then cooled to 20 ° C, held for 2 hours and filtered off. The solid material was washed with ethanol and dried, yielding 30 g (88% yield) of the product.

Step 4. The solution of sodium hydroxide (27.4 g) in 150 ml of water was added to 32 g of 9-tosyl-9H-3,9'-bicarbazole dissolved in 300 ml of THF and 150 ml of methanol. The reaction mixture was refluxed overnight. Then, organic solvents were evaporated, added to 100 ml of brine and extracted with 3 × 200 ml of ethyl acetate, combined organic layers, dried over Na ₂ SO ₄ and evaporated. The residue was dissolved in 200 ml of CH ₂ Cl ₂ and absorbed on silica gel. Purified by column chromatography, eluting with gradient mixture of ethyl acetate: hexane from 10:90 to 15:85. The solid was crystallized from ethyl acetate / hexane mixture to give 17 g (78% yield) of pure material.

Step 5. Potassium carbonate (18.18 g, 132 mmol) was dissolved in water (75 mL), sonicated, and the solution was added to the solution of dibenzo [b, d] thiophen-4-ylboronic acid (10.00 g, 43 , 8 mmol) and 1,3-dibromobenzene (13.79 ml, 114 mmol) in toluene (200 ml). Catalyst was added (1.013 g, 0.877 mmol), degassed, heated under reflux for 24 h under N ₂ atmosphere. Cooled, evaporated, purified by chromatography on silica gel (250 g), eluting with hexane / CH ₂ Cl ₂ 99/1. Chromatographed material was then crystallized from hexane to give white solid, 10.5 g (67% yield).

Step 6. 4- (3-Bromophenyl) dibenzo [b, d] thiophene (14.14 g, 41.7 mmol) was dissolved in dioxane (200 ml) to give a colorless solution. 4,4,4 ', 4', 5,5,5 ', 5'-octamethyl-2,2'-bi (1,3,2-dioxaborolane) (12.70g, 50.0mmol) was added in one portion, followed by potassium acetate (8.18 g, 83 mmol), Pd ₂ (dba) ₃ (0.382 g, 0.417 mmol) and 1,1'-bis (diphenylphosphino) ferrocene (dppf, 0.254 g, 0.834 mmol). , then the reaction mixture was degassed. Refluxed under N ₂ overnight, cooled, diluted with ethyl acetate (150 ml), washed with brine, NaHSO ₃ and 10% aqueous LiCl solution. Filtrated, evaporated, the residue was purified by column chromatography (silica 250g, Hex / Dcm 9: 1) to give 2- (3- (dibenzo [b, d] thiophen-4-yl) phenyl) -4.4, 5,5-tetramethyl-1,3,2-dioxaborolane as a white solid gave 12.8 g (80% yield).

Step 7. 2- (3- (Dibenzo [b, d] thiophen-4-yl) phenyl) -4,4,5,5-tetramethyl-1,3,2-dioxaborolane (14.50 g, 37.5%) mmol), 1,3-dibromobenzene (26.6 g, 113 mmol) was dissolved in 200 mL of toluene, aqueous K ₂ CO ₃ solution (16 g in 100 mL) added, followed by tetrakis (triphenylphosphine) palladium (0). (0.434g). The reaction mixture was degassed, filled with N ₂ , under N ₂ Atm. heated to reflux overnight. The organic layer was separated, dried over sodium sulfate, filtered and evaporated. The residue was purified by column chromatography on silica column (200 g, eluted with hexane / CH ₂ Cl ₂ 95: 5), then crystallized from hexane to give white solid, 10.1 g (65% yield).

Step 8. 4- (3'-Bromo [1,1'-biphenyl] -3-yl) dibenzo [b, d] thiophene (6.20 g, 14.93 mmol), 9H-3, 9'- Bicarbazole (4.96 g, 14.93 mmol) was suspended in xylene (dry, 200 mL), Pd ₂ dba ₃ (0.273 g, 0.299 mmol), dicyclohexyl (2 ', 6'-dimethoxy- [1,1'] -biphenyl] -3-yl) phosphine (0.245 g, 0.597 mmol) and sodium 2-methylpropan-2-olate (2.87 g, 29.9 mmol) were added, degassed, with vigorous stirring under N ₂ -Atm. Heated under reflux for 24 h. The hot reaction mixture was filtered through a pad of celite, concentrated and applied to a silica column (250 g). Eluted with hexane / CH ₂ Cl ₂ 4: 1, concentrated fractions, pure by TLC and HPLC. White solid precipitated, washed with hexane and crystallized from ethyl acetate to give compound 1 as a white solid (8.5 g, 85% yield).

device Examples

Several devices were made comprising the compounds of the invention. The anode electrode is ≈800 Å indium tin oxide (ITO). The cathode was 10 Å LiF followed by 1000 Å Al. All devices were encapsulated with a glass lid sealed with an epoxy resin in a nitrogen glove box (<1 ppm H ₂ O and O ₂ ) and a moisture scavenger was incorporated into the package.

As used herein, the following compounds have the following structures:

Solution based processed devices:

Device Example 1 was made as described below. Compound E and Compound G were dissolved in cyclohexanone. The amount of compound G in the solution was 10% by weight based on HIL-1. The total concentration of compound E and compound G was 0.5% by weight in cyclohexanone. To form the hole injection layer (HIL), the solution was spin coated for 60 seconds at 4,000 rpm onto a patterned indium-tin-oxide (ITO) electrode. The resulting film was baked at 250 ° C for 30 minutes. The film was insoluble after firing. At the top of the HIL, a hole transport layer (HTL) was applied followed by an emitting layer (EML), also by spin coating. The HTL was prepared by spin-coating a solution of 0.5% by weight of compound F in toluene at 4,000 rpm for 60 seconds. The HTL film was baked at 200 ° C for 30 minutes. After firing, the HTL was an insoluble film. To form the EMS, a toluene solution containing 80% of Compound 1 and 20% of Compound D (net concentration of 1 wt% in toluene) was spin-coated at 1000 rpm for 60 seconds on top of the insoluble HTL and then fired at 80 ° C for 60 minutes to remove solvent residues. Subsequently, a 50Å thick layer of compound C was vacuum evaporated as the blocking layer (BL) by thermal evaporation. Subsequently, a 200 Å thick layer of Alq _{3 was} vacuum evaporated as the electron transport layer (ETL) by thermal evaporation.

Comparative Example 1 was prepared in a similar manner except that the host was Compound C instead of Compound 1. The device data are shown in Table 2. Table 2. example host Dopants (conc.) ETL2 At 10 mA / cm ² At L ₀ = 2,000 cd / m ² 1931 CIE Voltage (V) LE (cd / A) LT ₈₀ (h) Device Example 1 Volume 1 20% Vbdg C (0.18, 0.38) 10 14.4 153 Comparative Device Example 2 Vbdg C 20% Compd (0.18, 0.38) 9.5 19.1 39

Devices by vacuum-thermal evaporation:

Device Examples 2 and 3 and Comparative Device Examples 2 to 9 were fabricated by thermal evaporation under high vacuum (<10 ^-7 Torr). The organic stack of the device examples 2 and 3 and the comparative device examples 2 to 9 in Table 3 consist, successively, of the ITO surface of 100 Å of compound D as the hole injection layer (HIL), 300 Å of α-NPD as the Hole transport layer (HTL), 300 Å of Compound 1, Compound B or Compound C doped with 15% by weight of Compound D, as the emissive layer (EML), 50 Å of Compound 1, Compound B, Compound C, Compound III or Compound IV as the blocking layer (BL) and 400 Å of Alq ₃ as the electron transport layer (ETL). The device structure and the result are shown in Table 3.

* berechnet auf Grundlage der Lebensdauerprüfung bei J = 20 mA/cm².Table 2 summarizes the data of the solution-based devices. Device Example 1 has significantly higher operational stability over Comparative Device Example 1. LT ₈₀ (defined as the time required for the initial luminance L ₀ to decrease from 100% to 90% under a constant current density at room temperature) of device example 1 is 153h, whereas that of comparative device example 1 is 39h. Although the luminance efficiency (LE) at J = 10 mA / cm ² of comparative device example 1 is higher (19.1 cd / A), device example 1 is still quite efficient (14.4 cd / A). Table 3.

* calculated on the basis of the life test at J = 20 mA / cm ² .

Table 3 summarizes the data of the devices by vacuum thermal evaporation. Device Example 2 and Comparative Device Example 2 have the same structure except that Device Example 2 has Compound 1 as the host, whereas Comparative Device Example 2 has Compound C as the host. The two devices have similar efficiency (≈16% EQE). However, Device Example 2 is significant compared to Comparative Device Example 2 stable. LT ₈₀ of Device Example 2 is 1063 hours, whereas Comparative Device Example 2 is 600 hours. Device example 3 and comparison device example 3 have the same structure except that device example 3 has connection 1 as the host and BL, whereas comparison device example 3 has connection B as the host and the BL. The two devices have similar efficiency (≈16% EQE). However, Device Example 3 is significantly more stable compared to Comparative Device Example 3. LT ₈₀ of Device Example 3 is 861h whereas that of Comparative Device Example 1 is 604h. Device Example 2 and Comparative Device Example 4 have the same structure except that Device Example 2 has Compound 1 as the host, whereas Comparative Device Example 4 has Compound I as the host. Device Example 2 not only has higher efficiency, but is significantly more stable compared to Comparative Device Example 4. LT ₈₀ of device example 2 is 1063 h, whereas that of comparison device example 4 is 530 h.

The data suggest two superior features of formula I compounds. First, compound 1 gives a 3,9-linked oligocarbazole moiety and a dibenzothiophene moiety linked by an aromatic group as compared to compounds having 3,9-linked oligocarbazole moiety and dibenzothiophene moiety attached directly , a high stability of the device. It is believed that the presence of an aromatic linker has an effect on conjugation and thus improves the stability of the device. Secondly, compounds having carbazole and dibenzothiophene moieties are inferior to compounds having 3,9-linked oligocarbazole and dibenzothiophene moieties, even with an aromatic linker. 3,9-linked oligocarbazole, the major HOMO contributor in the compounds provided herein, is more electron-rich than carbazole. The oxidation and reduction potential of compound 1 is 0.74 V and -2.73 V, respectively (vs. Fc / Fc ⁺ ). The oxidation and reduction potential of Compound C is 0.91 V and -2.84, respectively. The higher HOMO level of Compound 1 can increase hole injection from HTL and hole transport in EML. This may result in better charge balance and / or location of charge recombination of the device resulting in improved device life.

The oxidation and reduction potential of compound B is 0.74 V and -2.78, respectively. While the HOMO levels of compound 1 and compound B are similar, the LUMO level of compound 1 is due to the additional π system, which is provided by the biphenyl linker, somewhat lower. In general, in compounds containing a 3,9-linked oligocarbazole moiety and a dibenzothiophene moiety with an aromatic linker, control over π-conjugation, thermal properties and further structural / electronic modification by substituents is better than in corresponding ones Compounds without an aromatic linker. It is believed that Compound 1, in addition to the difference in electronic properties, provides better morphology and morphological stability as compared to Compound B and Compound C, resulting in improved device life. In particular, materials having an asymmetric structure, such as. For example, the 3,9-linked oligocarbazole structure can provide improved film formation. It is believed that the improved film formation results from the reduced crystallization due to the asymmetric structure of the compound. This has been demonstrated by unexpected results from solution-based devices using the compounds as a host material.

It should be understood that the various embodiments described herein are only examples and are not intended to limit the scope of the invention. For example, many of the materials and structures described herein may be replaced by other materials and structures without departing from the spirit of the invention. The present invention as claimed may therefore include variants of the particular examples and preferred embodiments described herein, as will be apparent to those skilled in the art. It should be understood that various theories as to why the invention works should not be limiting.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• US 5844363 [0005, 0042]
• US 6,303,338 [0005, 0042]
• US 5707745 [0005, 0042, 0045]
• US 7279704 [0015, 0040, 0041, 0049]
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Cited non-patent literature

• Baldo et al., "Highly Efficient Phosphorescent Emission from Organic Electroluminescent Devices," Nature, vol. 395, 151-154, 1998; ("Baldo-I") [0040]
• Baldo et al., "Very high-efficiency green organic light-emitting devices based on electrophosphorescence," Appl. Phys. Lett., Vol. 75, no. 3, 4-6 (1999) ("Baldo-II") [0040]

Claims (21)

Connection with the formula:

where n is 1 to 20; wherein each of R ' ₁ , R' ₂ , R ' ₃ and R' ₄ independently represents mono-, di-, tri- or tetrasubstitutions; wherein R ' ₁ , R' ₂ , R ' ₃ and R' _{4 are} independently selected from the group consisting of hydrogen, deuterium, alkyl, alkoxy, amino, alkenyl, alkynyl, arylalkyl, aryl and heteroaryl; wherein R _a and R _b independently represent mono-, di-, tri- or tetrasubstitutions; wherein R _a and R _{b are} independently selected from the group consisting of hydrogen, deuterium, alkyl, alkoxy, amino, alkenyl, alkynyl, arylalkyl, aryl and heteroaryl; wherein X is an aryl or heteroaryl linker which is further substituted with R _a ; and wherein Y is dibenzothiophene, dibenzofuran, dibenzoselenophene, aza-dibenzothiophene, aza-dibenzofuran or aza-dibenzoselenophen, which is further substituted with R _b . A compound according to claim 1, wherein n is 1, 2 or 3. A compound according to claim 1, wherein n is 1. The compound of claim 1, wherein X is

wherein A, B, C and D are independently selected from the group consisting of:

wherein A, B, C and D are optionally further substituted with R _a ; wherein each of p, q, r and s is 0, 1, 2, 3 or 4; and where p + q + r + s is at least 1. A compound according to claim 1, wherein Y is 2-dibenzothiophenyl, 4-dibenzothiophenyl, 2-dibenzofuranyl or 4-dibenzofuranyl. The compound of claim 1, wherein the compound is selected from the group consisting of:

A first device comprising an organic light-emitting device comprising: an anode; a cathode; and a first organic layer disposed between the anode and the cathode comprising a compound having the formula:

where n is 1 to 20; wherein each of R ' ₁ , R' ₂ , R ' ₃ and R' ₄ independently represents mono-, di-, tri- or tetrasubstitutions; wherein R ' ₁ , R' ₂ , R ' ₃ and R' _{4 are} independently selected from the group consisting of hydrogen, deuterium, alkyl, alkoxy, amino, alkenyl, alkynyl, arylalkyl, aryl and heteroaryl; wherein R _a and R _b independently represent mono-, di-, tri- or tetrasubstitutions; wherein R _a and R _{b are} independently selected from the group consisting of hydrogen, deuterium, alkyl, alkoxy, amino, alkenyl, alkynyl, arylalkyl, aryl and heteroaryl; wherein X is an aryl or heteroaryl linker which is further substituted with R _a ; and wherein Y is dibenzothiophene, dibenzofuran, dibenzoselenophene, aza-dibenzothiophene, aza-dibenzofuran or aza-dibenzoselenophen, which is further substituted with R _b . The first device of claim 7, wherein n is 1 to 20. The first device of claim 7, wherein n is 1, 2 or 3. The first device according to claim 7, wherein X

wherein A, B, C and D are independently selected from the group consisting of:

wherein A, B, C and D are optionally further substituted with R _a ; wherein each of p, q, r and s is 0, 1, 2, 3 or 4; and where p + q + r + s is at least 1. The first device of claim 7, wherein Y is 2-dibenzothiophenyl, 4-dibenzothiophenyl, 2-dibenzofuranyl or 4-dibenzofuranyl. The first device of claim 7, wherein the compound is selected from the group consisting of:

The first device according to claim 7, wherein the first organic layer is an emitting layer and the connection with the

The first device of claim 13, wherein the first organic layer further comprises an emitting dopant having the formula

wherein A is a 5- or 6-membered carbocyclic or heterocyclic ring; wherein R ₁ , R ₂ and R ₃ independently represent mono-, di-, tri- or tetrasubstituenten; wherein each of R ₁ , R ₂ and R _{3 is} independently selected from the group consisting of hydrogen, deuterium, alkyl, alkoxy, amino, alkenyl, alkynyl, arylalkyl, aryl and heteroaryl; where n is 1, 2 or 3; and wherein X-Y is an auxiliary ligand. The first device of claim 14, wherein the emitting dopant is selected from the group consisting of:

The first device of claim 7, wherein the device further comprises a second organic layer that is a non-emitting layer and the compound of formula I is a material in the second organic layer. The first device of claim 16, wherein the second organic layer is an electron transport layer and the compound of formula I is an electron transport material in the second organic layer. The first device of claim 16, wherein the second organic layer is a blocking layer and the compound of formula I is a blocking material in the second organic layer. The first device of claim 7, wherein the first organic layer is deposited using solution-based processing. The first device according to claim 7, wherein the device is an organic light-emitting device. The first device according to claim 7, wherein the device is a consumer good.

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